[Edit] Implement EditToolbar

Implement EditToolbar (sufficient to satisfy spec) which will
construct an mct-toolbar-friendly form structure based on both
the current selection and the view's defined toolbar structure.
WTD-878.

platform/commonUI/edit/src/representers/EditToolbar.js

@@ -4,17 +4,162 @@ define(
     function () {
         "use strict";
 
+        // Utility functions for reducing truth arrays
+        function and(a, b) { return a && b; }
+        function or(a, b) { return a || b; }
+
+
+        /**
+         * Provides initial structure and state (as suitable for provision
+         * to the `mct-toolbar` directive) for a view's tool bar, based on
+         * that view's declaration of what belongs in its tool bar and on
+         * the current selection.
+         *
+         * @param structure toolbar structure, as provided by view definition
+         * @param {Array} selection the current selection state
+         * @constructor
+         */
         function EditToolbar(structure, selection) {
+            var toolbarStructure = Object.create(structure || {}),
+                toolbarState,
+                properties = [];
+
+            // Generate a new key for an item's property
+            function addKey(property) {
+                properties.push(property);
+                return properties.length - 1; // Return index of property
+            }
+
+            // Update value for this property in all elements of the
+            // selection which have this property.
+            function updateProperties(property, value) {
+                // Update property in a selected element
+                function updateProperty(selected) {
+                    // Ignore selected elements which don't have this property
+                    if (selected[property] !== undefined) {
+                        // Check if this is a setter, or just assignable
+                        if (typeof selected[property] === 'function') {
+                            selected[property](value);
+                        } else {
+                            selected[property] = value;
+                        }
+                    }
+                }
+
+                // Update property in all selected elements
+                selection.forEach(updateProperty);
+            }
+
+            // Look up the current value associated with a property
+            // in selection i
+            function lookupState(property, selected) {
+                var value = selected[property];
+                return (typeof value === 'function') ? value() : value;
+            }
+
+            // Get initial value for a given property
+            function initializeState(property) {
+                var result;
+                // Look through all selections for this property;
+                // values should all match by the time we perform
+                // this lookup anyway.
+                selection.forEach(function (selected) {
+                    result = (selected[property] !== undefined) ?
+                            lookupState(property, selected) :
+                            result;
+                });
+                return result;
+            }
+
+            // Check if all elements of the selection which have this
+            // property have the same value for this property.
+            function isConsistent(property) {
+                var consistent = true,
+                    observed = false,
+                    state;
+
+                // Check if a given element of the selection is consistent
+                // with previously-observed elements for this property.
+                function checkConsistency(selected) {
+                    var next;
+                    // Ignore selections which don't have this property
+                    if (selected[property] !== undefined) {
+                        // Look up state of this element in the selection
+                        next = lookupState(property, selected);
+                        // Detect inconsistency
+                        if (observed) {
+                            consistent = consistent && (next === state);
+                        }
+                        // Track state for next iteration
+                        state = next;
+                        observed = true;
+                    }
+                }
+
+                // Iterate through selections
+                selection.forEach(checkConsistency);
+
+                return consistent;
+            }
+
+            // Used to filter out items which are applicable (or not)
+            // to the current selection.
+            function isApplicable(item) {
+                var property = (item || {}).property,
+                    exclusive = !(item || {}).inclusive;
+
+                // Check if a selected item defines this property
+                function hasProperty(selected) {
+                    return selected[property] !== undefined;
+                }
+
+                return property && selection.map(hasProperty).reduce(
+                    exclusive ? and : or,
+                    exclusive
+                ) && isConsistent(property);
+            }
+
+            // Prepare a toolbar item based on current selection
+            function convertItem(item) {
+                var converted = Object.create(item || {});
+                converted.key = addKey(item.property);
+                return converted;
+            }
+
+            // Used to filter out sections that have become empty
+            function nonEmpty(section) {
+                return section && section.items && section.items.length > 0;
+            }
+
+            // Prepare a toolbar section based on current selection
+            function convertSection(section) {
+                var converted = Object.create(section || {});
+                converted.items =
+                    ((section || {}).items || [])
+                            .map(convertItem)
+                            .filter(isApplicable);
+                return converted;
+            }
+
+            toolbarStructure.sections =
+                ((structure || {}).sections || [])
+                        .map(convertSection)
+                        .filter(nonEmpty);
+
+            toolbarState = properties.map(initializeState);
 
             return {
+                /**
+                 *
+                 */
                 getStructure: function () {
-
+                    return toolbarStructure;
                 },
                 getState: function () {
-
+                    return toolbarState;
                 },
-                updateState: function (key) {
-
+                updateState: function (key, value) {
+                    updateProperties(properties[key], value);
                 }
             };
         }

platform/commonUI/edit/test/representers/EditToolbarSpec.js

@@ -35,8 +35,8 @@ define(
                 testAB = { a: 0, b: 1 };
                 testABC = { a: 0, b: 1, c: 2 };
                 testABC2 = { a: 4, b: 1, c: 2 }; // For inconsistent-state checking
-                testABCXYZ = { a: 'A!', b: 'B!', c: 'C!', x: 'X!', y: 'Y!', z: 'Z!' };
-                testABCYZ = { a: 'A!', b: 'B!', c: 'C!', y: 'Y!', z: 'Z!' };
+                testABCXYZ = { a: 0, b: 1, c: 2, x: 'X!', y: 'Y!', z: 'Z!' };
+                testABCYZ = { a: 0, b: 1, c: 2, y: 'Y!', z: 'Z!' };
             });
 
             it("provides properties from the original structure", function () {